1. Technical Field
The present invention is directed in general to an improved impact printer and more particularly to an improved font system for utilization with a high character density impact printer system. Still more particularly the present invention is related to an improved low pel density font system for utilization with a high character density impact printer system.
2. Description of the Related Art
So-called "dot-matrix" printers are known in the prior art. Such printers typically take the form of a print head having a number of print pins or wires which are arranged in rows and columns wherein the pins may be individually actuated in combinations in a manner well known in the art to print characters as the print head is moved across a piece of paper or other material upon which it is desired to print characters. Dot printers may also be implemented utilizing an ink jet printer which utilizes a number of individual ink jets out of which droplets of ink are pulsed in combinations to print characters as a sequence of dots.
Dot printers such as the type described herein are capable of printing at speeds faster than other mechanical printers such as conventional typewriter or daisy wheel printers; however, the print resolution or quality of existing dot printers is generally inferior to the resolution or quality of print obtained from typewriters and daisy wheel printers. This is due to the fact that the dots making up the characters are discrete unconnected dots and thereby yield low print resolution. In addition, due primarily to the low print resolution the ability to provide variable print fonts is greatly limited.
A typical dot matrix character formed by such a system is generally created by sequentially moving the print head across the paper and selectively actuating various pins or wires which are arranged either vertically or horizontally on the head.
Modern impact type dot printers are also capable of printing high density imprints in a selected mode of operation by overlapping the imprints of the dots which are utilized to form the characters; however, this technique typically requires additional time and greater complexity of control circuitry.
Typically, a printed character for matrix printers in standard print quality mode is created by printing appropriate dots within a 7.times.4 cell character matrix which is seven dots high and four dots wide. In a normal system the pel density in the vertical direction is generally seventy-two pels per inch and in the horizontal direction the pel density is sixty pels per inch. Thus, printing can occur at a character density of ten characters per inch, allowing four horizontal characters for each letter with one pel on each side of the character for spacing.
However, if higher character density is desired in a system with a fixed pel density the character matrix for each character must necessarily be smaller in horizontal dimension. A reduction in the size of the character matrix often results in a perception of poor print quality as certain letters are not easily formed utilizing smaller character matrixes.
It should thus be apparent that a need exists for a method and system which permits high character density printing to occur within a low pel density printer.